The present invention relates to inspection systems, and more particularly to mechanisms for inspecting in-process container closures.
In the production and processing of metallic closures for containers it is desirable to identify and eliminate defective closures before they are permanently affixed to containers. In view of the mass production techniques which are required to produce closures and containers economically, inspection of closure members has commonly been foregone in some respects. The difficulty in devising systems to rapidly and accurately check individual closures has caused container manufacturers to implement processes in which the containers were not fully checked until they had been filled and pressurized. While this makes inspection considerably easier, it obviously entails substantial expense and waste. Nonetheless, until now it has been considered more practical than attempting to inspect each individual closure member while in process. Aerosol container closures are commonly crimped over the open mouth of an open-ended cylindrical can. In order to assure a pressure-tight joint it is conventional to apply a bead of sealing compound about the periphery of the closure, before it is assembled to the container body. Checking for the continuity of the sealing bead has presented formidable problems, owing in part to the number and speed with which container closures are produced and conveyed during the manufacturing and assembly process. Still another chronic problem with state-of-the-art aerosol closures is the cracking or splitting of a curled flange at the uppermost edge of the closure. Such cracks or splits are often very hard to recognize, even by visual inspection. Again, the inspection problems are increased substantially due to the number and rate of production of closures. Finally, the cost of floor space in a container manufacturing plant is such as to discourage the use of large and elaborate testing facilities, particularly wherein such facilities must include multiple paths to allow for automatically inspecting closures at a rate less than that at which they are being produced. Accordingly, it will be appreciated that it would be desirable to provide a compact apparatus which will quickly and economically inspect succesive in-process metallic closures.
It is therefore an object of the present invention to provide means for determining the integrity of sealing compound applied to metallic container closures.
Another object is to provide means for detecting split curls in metallic closures.
Yet another object is to provide improved apparatus for detecting defects in in-process metallic closures and discharging the closures in timed relationship with their advance along a predetermined path.
Still another object is to provide a method for inspecting metallic closures for the presence of sealing compound.
Yet another object of the invention is to provide a method for simultaneously inspecting metallic closures for the absence of sealing compound, and for split curls.